Module Name: src
Committed By: uebayasi
Date: Tue Apr 15 15:50:16 UTC 2014
Modified Files:
src/sys/kern: kern_exec.c
Log Message:
exec_loadvm: Isolate stack size calc logic into separate functions.
To generate a diff of this commit:
cvs rdiff -u -r1.395 -r1.396 src/sys/kern/kern_exec.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_exec.c
diff -u src/sys/kern/kern_exec.c:1.395 src/sys/kern/kern_exec.c:1.396
--- src/sys/kern/kern_exec.c:1.395 Mon Apr 14 13:14:38 2014
+++ src/sys/kern/kern_exec.c Tue Apr 15 15:50:16 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_exec.c,v 1.395 2014/04/14 13:14:38 uebayasi Exp $ */
+/* $NetBSD: kern_exec.c,v 1.396 2014/04/15 15:50:16 uebayasi Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.395 2014/04/14 13:14:38 uebayasi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.396 2014/04/15 15:50:16 uebayasi Exp $");
#include "opt_exec.h"
#include "opt_execfmt.h"
@@ -122,6 +122,8 @@ __KERNEL_RCSID(0, "$NetBSD: kern_exec.c,
struct execve_data;
+static size_t calcargs(struct execve_data * restrict, const size_t);
+static size_t calcstack(struct execve_data * restrict, const size_t);
static int copyinargs(struct execve_data * restrict, char * const *,
char * const *, execve_fetch_element_t, char **);
static int copyinargstrs(struct execve_data * restrict, char * const *,
@@ -250,6 +252,7 @@ struct execve_data {
char *ed_resolvedpathbuf;
size_t ed_ps_strings_sz;
int ed_szsigcode;
+ size_t ed_argslen;
long ed_argc;
long ed_envc;
};
@@ -700,29 +703,10 @@ execve_loadvm(struct lwp *l, const char
* Calculate the new stack size.
*/
- const size_t nargenvptrs =
- data->ed_argc + /* char *argv[] */
- 1 + /* \0 */
- data->ed_envc + /* char *env[] */
- 1 + /* \0 */
- epp->ep_esch->es_arglen; /* auxinfo */
-
- const size_t ptrsz = (epp->ep_flags & EXEC_32) ?
- sizeof(int) : sizeof(char *);
-
- const size_t argenvstrlen = (char *)ALIGN(dp) - data->ed_argp;
-
- data->ed_szsigcode = epp->ep_esch->es_emul->e_esigcode -
- epp->ep_esch->es_emul->e_sigcode;
-
- data->ed_ps_strings_sz = (epp->ep_flags & EXEC_32) ?
- sizeof(struct ps_strings32) : sizeof(struct ps_strings);
-
- const size_t aslrgap =
#ifdef PAX_ASLR
- pax_aslr_active(l) ? (cprng_fast32() % PAGE_SIZE) : 0;
+#define ASLR_GAP(l) (pax_aslr_active(l) ? (cprng_fast32() % PAGE_SIZE) : 0)
#else
- 0;
+#define ASLR_GAP(l) 0
#endif
#ifdef __MACHINE_STACK_GROWS_UP
@@ -736,32 +720,19 @@ execve_loadvm(struct lwp *l, const char
#define RTLD_GAP 0
#endif
- const size_t argenvlen =
- RTLD_GAP + /* reserved for _rtld() */
- sizeof(int) + /* XXX argc in stack is long, not int */
- (nargenvptrs * ptrsz); /* XXX auxinfo multiplied by ptr size? */
+ const size_t argenvstrlen = (char *)ALIGN(dp) - data->ed_argp;
- const size_t sigcode_psstr_sz =
- data->ed_szsigcode + /* sigcode */
- data->ed_ps_strings_sz + /* ps_strings */
- STACK_PTHREADSPACE; /* pthread space */
+ data->ed_argslen = calcargs(data, argenvstrlen);
- const size_t stacklen =
- argenvlen +
- argenvstrlen +
- aslrgap +
- sigcode_psstr_sz;
-
- /* make the stack "safely" aligned */
- const size_t aligned_stacklen = STACK_LEN_ALIGN(stacklen, STACK_ALIGNBYTES);
+ const size_t len = calcstack(data, ASLR_GAP(l) + RTLD_GAP);
- if (aligned_stacklen > epp->ep_ssize) {
+ if (len > epp->ep_ssize) {
/* in effect, compare to initial limit */
- DPRINTF(("%s: stack limit exceeded %zu\n", __func__, aligned_stacklen));
+ DPRINTF(("%s: stack limit exceeded %zu\n", __func__, len));
goto bad;
}
/* adjust "active stack depth" for process VSZ */
- epp->ep_ssize = aligned_stacklen;
+ epp->ep_ssize = len;
return 0;
@@ -1397,6 +1368,53 @@ execve1(struct lwp *l, const char *path,
return error;
}
+static size_t
+calcargs(struct execve_data * restrict data, const size_t argenvstrlen)
+{
+ struct exec_package * const epp = &data->ed_pack;
+
+ const size_t nargenvptrs =
+ data->ed_argc + /* char *argv[] */
+ 1 + /* \0 */
+ data->ed_envc + /* char *env[] */
+ 1 + /* \0 */
+ epp->ep_esch->es_arglen; /* auxinfo */
+
+ const size_t ptrsz = (epp->ep_flags & EXEC_32) ?
+ sizeof(int) : sizeof(char *);
+
+ const size_t argenvlen =
+ sizeof(int) + /* XXX argc in stack is long, not int */
+ (nargenvptrs * ptrsz); /* XXX auxinfo multiplied by ptr size? */
+
+ return argenvlen + argenvstrlen;
+}
+
+static size_t
+calcstack(struct execve_data * restrict data, const size_t gaplen)
+{
+ struct exec_package * const epp = &data->ed_pack;
+
+ data->ed_szsigcode = epp->ep_esch->es_emul->e_esigcode -
+ epp->ep_esch->es_emul->e_sigcode;
+
+ data->ed_ps_strings_sz = (epp->ep_flags & EXEC_32) ?
+ sizeof(struct ps_strings32) : sizeof(struct ps_strings);
+
+ const size_t sigcode_psstr_sz =
+ data->ed_szsigcode + /* sigcode */
+ data->ed_ps_strings_sz + /* ps_strings */
+ STACK_PTHREADSPACE; /* pthread space */
+
+ const size_t stacklen =
+ data->ed_argslen +
+ gaplen +
+ sigcode_psstr_sz;
+
+ /* make the stack "safely" aligned */
+ return STACK_LEN_ALIGN(stacklen, STACK_ALIGNBYTES);
+}
+
static int
copyinargs(struct execve_data * restrict data, char * const *args,
char * const *envs, execve_fetch_element_t fetch_element, char **dpp)
